At the bottom of the shaft we put in sumps from which to pump the water, and then proceeded to drive our galleries ahead.
These sumps have been described in a previous part of this paper; they were put down without trouble.
And by having two sumps or bottom cisterns, your water may, in some measure, settle in one of them in its passage to the other.
The water drops directly from the drains in the center lines of the tunnels into the sumps.
The sumps were really short tunnels underneath the main ones and extending approximately between the center lines of the latter.
From the preliminary borings it was thought that the sumps were located so that the entire construction would be in rock.